EXHIBIT A

Joint Filing Statement

We, the undersigned, hereby express our agreement that the attached Schedule 13G is filed on behalf of each of us.

Date: February 14, 2018

INTERWEST PARTNERS X, LP

By: InterWest Management Partners X, LLC, its General Partner

By:	/s/ Gilbert H. Kliman
	Managing Director

INTERWEST MANAGEMENT PARTNERS X, LLC

By:	/s/ Gilbert H. Kliman
	Managing Director

By:	/s/ Keval Desai
Name:	Keval Desai

By:	/s/ Philip T. Gianos
Name:	Philip T. Gianos

By:	/s/ W. Stephen Holmes by Karen A. Wilson, Power of Attorney
Name:	W. Stephen Holmes

By:	/s/ Gilbert H. Kliman
Name:	Gilbert H. Kliman

By:	/s/ Khaled A. Nasr
Name:	Khaled A. Nasr

By:	/s/ Arnold L. Oronsky
Name:	Arnold L. Oronsky

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